The present invention relates to an X-ray film cassette used for an X-ray photographic apparatus of such as medical usage, particularly to a front plate of the X-ray film cassette. The front plate means the plate of the X-ray film cassette opposed to an X-ray source.
An X-ray film cassette is generally composed of a front plate opposed to the X-ray source, a frame mounted on the periphery of the front plate, and a back plate mounted on the periphery of the frame, thereby to form a housing for receiving the X-ray films therein.
Hitherto, an aluminum plate or Bakelite plate has generally been used as a front plate of the X-ray film cassette for the reason that the aluminum plate or the Bakelite plate has a good x-ray transmissivity, a good transportation facility due to light weight and a good characteristic due to homogeneity of material. However, it has recently been proposed to utilize for the front plate of the X-ray film cassette, a plate having a X-ray transparent material layer, such as plywood and a laminated thermosetting resin plate including cotton sandwiched between carbon fiber reinforced plastic layers, and adhered to the carbon fiber reinforced plastic layers to form an integrally laminated body. Such a plate is disclosed in Japanese Utility Model Application Laid-Open No. 121,467/76.
The above mentioned front plate has a good transportation facility due to light weight in comparison with the conventional front plate, and further has a good flexural strength and modulus for bending. therefore the above mentioned proposed front plate has an advantage that the front plate is substantially unaffected by the stress generated in retaining a film and a sensitized paper in close contact with each other in the film cassette.
However, it is usual to transport a plurality of the X-ray film cassettes, and the X-ray film cassettes are sometimes drapped during the transporation, a collecting operation or a stacking operation, whereby the front plate of the cassette can be struck by the corner of other cassette. A conventional front plate of the X-ray film cassette can develop surface cracks as a result of such imports. The cracks thus produced appear on an X-ray photographic image thereby reducing the image quality of the X-ray photography. Therefore, a front plate of an X-ray film cassette not susceptible such cracks would be highly useful.